Apparently, the final version of the nv40 chipset (used in the GT and ultra 6800 class) has been tweaked, specifically the BIOS and the actual hardware itself. Nvidia has lowered the power requirements to 380W, or 100W down from 480W. That means if you own a generic 380W PSU and a 6800 ultra, it certainly possible that both can be used in tandem. Also, I remember reading somewhere that they removed the power connector from the card on PCIe versions of the card, suggesting that the card consumes less than 75W. Anyway, all of this should explain why a 250W quality SFF PSU MAY (and I strongly emphasize the word "MAY") be able to work in tandem with an 6800 class Nvidia card.